feat: Implement document saving with reindexing

- Updated the document saving endpoint to trigger reindexing after saving.
- Introduced a new Celery task for reindexing documents.
- Refactored the editor page to reflect the changes in the API endpoint and method.

surfsense_backend/app/tasks/celery_tasks/document_reindex_tasks.py

@@ -0,0 +1,128 @@
+"""Celery tasks for reindexing edited documents."""
+
+import logging
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.pool import NullPool
+from sqlalchemy import delete
+from sqlalchemy.orm import selectinload
+
+from app.celery_app import celery_app
+from app.config import config
+from app.db import Document
+from app.utils.blocknote_converter import convert_blocknote_to_markdown
+from app.utils.document_converters import (
+    create_document_chunks,
+    generate_document_summary,
+)
+from app.services.llm_service import get_user_long_context_llm
+
+logger = logging.getLogger(__name__)
+
+
+def get_celery_session_maker():
+    """Create async session maker for Celery tasks."""
+    engine = create_async_engine(
+        config.DATABASE_URL,
+        poolclass=NullPool,
+        echo=False,
+    )
+    return async_sessionmaker(engine, expire_on_commit=False)
+
+
+@celery_app.task(name="reindex_document", bind=True)
+def reindex_document_task(self, document_id: int, user_id: str):
+    """
+    Celery task to reindex a document after editing.
+    
+    Args:
+        document_id: ID of document to reindex
+        user_id: ID of user who edited the document
+    """
+    import asyncio
+
+    loop = asyncio.new_event_loop()
+    asyncio.set_event_loop(loop)
+
+    try:
+        loop.run_until_complete(_reindex_document(document_id, user_id))
+    finally:
+        loop.close()
+
+
+async def _reindex_document(document_id: int, user_id: str):
+    """Async function to reindex a document."""
+    async with get_celery_session_maker()() as session:
+        try:
+            # Get document
+            result = await session.execute(
+                select(Document)
+                .options(selectinload(Document.chunks))  # Eagerly load chunks
+                .where(Document.id == document_id)
+            )
+            document = result.scalars().first()
+            
+            if not document:
+                logger.error(f"Document {document_id} not found")
+                return
+            
+            if not document.blocknote_document:
+                logger.warning(f"Document {document_id} has no BlockNote content")
+                return
+            
+            logger.info(f"Reindexing document {document_id} ({document.title})")
+            
+            # 1. Convert BlockNote → Markdown
+            markdown_content = await convert_blocknote_to_markdown(
+                document.blocknote_document
+            )
+            
+            if not markdown_content:
+                logger.error(f"Failed to convert document {document_id} to markdown")
+                return
+            
+            # 2. Delete old chunks explicitly
+            from app.db import Chunk
+            await session.execute(
+                delete(Chunk).where(Chunk.document_id == document_id)
+            )
+            await session.flush()  # Ensure old chunks are deleted
+            
+            # 3. Create new chunks
+            new_chunks = await create_document_chunks(markdown_content)
+            
+            # 4. Add new chunks to session
+            for chunk in new_chunks:
+                chunk.document_id = document_id
+                session.add(chunk)
+            
+            logger.info(f"Created {len(new_chunks)} chunks for document {document_id}")
+            
+            # 5. Regenerate summary
+            user_llm = await get_user_long_context_llm(
+                session, user_id, document.search_space_id
+            )
+            
+            document_metadata = {
+                "title": document.title,
+                "document_type": document.document_type.value,
+            }
+            
+            summary_content, summary_embedding = await generate_document_summary(
+                markdown_content, user_llm, document_metadata
+            )
+            
+            # 6. Update document
+            document.content = summary_content
+            document.embedding = summary_embedding
+            document.content_needs_reindexing = False
+            
+            await session.commit()
+            
+            logger.info(f"Successfully reindexed document {document_id}")
+            
+        except Exception as e:
+            await session.rollback()
+            logger.error(f"Error reindexing document {document_id}: {e}", exc_info=True)
+            raise